High volume - high value usage of Flue Gas Desulfurization (FGD) by-products in underground mines. Quarterly report, October 1, 1995--December 31, 1995

The amount of dry FGD materials produced in the U.S. has not been increasing at the high rate originally anticipated. This has been due to a number of economic factors affecting the utility industry. Technologies for the disposal of large amounts of materials are not going to be implemented in the near term. In light of this development the target application for this project is being changed from highwall adit filling to the filling of auger holes to allow for highwall mining. This application focuses on using the dry FGD material to recover coal isolated by excessive augering. It produces 10 or more times the amount of coal per ton of dry FGD utilized than the originally proposed methodology. It also does not require extensive equipment development and, if applied to abandoned mine lands, may have substantially more significant environmental benefit. We also propose to use a spray dryer material for the demonstration instead of the fluidized bed material originally proposed. The spray dryer material is already slacked eliminating problems associated with heat generation at the mine site. Auger hole grouting with FGD material is also best performed by hydraulic emplacement methods